I use the helmets from ALDI, at around $14-$17 each. They have passed exactly the same safety/crash tests as those $300+ helmets. They are lighter than some of those too. The latest ones even have a flashing LED light built into them.

I have both a Specialized Prevail and Kask Vertigo and hands down the Kask Vertigo is far superior in my opinion.

Personally cannot go past the fit of the Vertigo. It just feels increasingly more secure on your head as opposed to that of the Specialised. The locking mechanism at the back of the helmet moves in much the same way the Specialized does not it also has silicon pads which gives you that secure feeling I was referring to above.

I found the chin straps on the Vertigo which are made out out of leather on the Vertigo to be far more superior than those found on the Specialized.